body{
    background-image: url(../img/表格背.jpeg);
    background-size: cover;
}
table tr:nth-child(1) td{
    color: black;
    font-size: 20px;
}
td{
    text-align: center;
}
table,tr,td{
    border: 1px solid black;
    border-collapse: collapse;
    text-align: center;
}
table{
    width: 1000px;
    height: 500px;
}

.ni{
    width: 1000px;
    position: absolute;
    top: 50%;
    right: 50%;
    transform: translate(50%,-50%);
}
td:nth-child(2n){
    background-color: aqua;
}
td:nth-child(2n+1){
    background-color: rgb(0, 255, 8);
}
